1. Field of the Invention
The present invention relates to a safety photoelectric switch.
2. Description of the Background Art
As seen in Japanese Patent Application Laid-Open No. H4-310890 and Japanese Patent Application Laid-Open No. H3-175390, an optical scanning type photoelectric switch is known which two-dimensionally performs scanning with light to detect an object while detecting a position of this object. As also referred to as a safety scanner, a safety laser scanner, and the like, this optical scanning type photoelectric switch provides a protection area around a machine, a robot or the like as a danger source, and outputs to the danger source a safety signal not permitting its operation when an operator or the like enters this protection area.
A photoelectric switch to serve as safety equipment is not restricted to the above optical scanning type photoelectric switch, but a multi-optical axis photoelectric switch and a single optical axis photoelectric switch are known. The multi-optical axis photoelectric switch is used for forming a light curtain at an entrance of the protection area, and in this multi-optical axis photoelectric switch, as one safety function, a blanking function is prepared which temporarily invalidates the whole or part of the area of the light curtain. As this blanking function, known are a floating blanking function which designates the number of optical axes and a fixing blanking function which designates an optical axis number (Japanese Patent Application Laid-Open No. 2002-296361, Japanese Patent Application Laid-Open No. 2003-20147).